US9333006B2 - Rotational atherectomy device - Google Patents

Abstract

A rotational atherectomy device for removing a stenotic tissue from a vessel of a patient is disclosed. The device comprises a rotatable, flexible, hollow drive shaft having an open distal end. The drive shaft comprising a fluid impermeable wall, an abrasive element mounted to the drive shaft proximal to and spaced away from its distal end, the fluid impermeable wall being formed from a torque transmitting coil and at least one fluid impermeable membrane which define a lumen for the antegrade flow of pressurized fluid through the drive shaft and into a distal fluid inflatable support element to inflate said fluid inflatable support element. The distal fluid inflatable support element is located at the distal end of the drive shaft and has an outer wall comprising an outflow opening.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation of U.S. application Ser. No. 13/412,212 (now U.S. Pat. No. 8,500,764) filed on Mar. 5, 2012, by Dr. Leonid Shturman, which is a continuation of U.S. application Ser. No. 12/373,418 (now U.S. Pat. No. 8,137,369) filed on Jan. 12, 2009, by Dr. Leonid Shturman, which is a national phase application based on PCT/EP2007/056500 filed on Jun. 28, 2007, which claims priority to GB Patent Application No. 0613980.2 filed on Jul. 13, 2006, the entire contents of these prior applications being incorporated herein by reference.

BACKGROUND

1. Field

The present invention provides a rotational atherectomy device for removing a stenotic lesion from within a vessel of a patient. More specifically, the invention relates to a rotational atherectomy device for removing or reducing stenotic lesions in blood vessels such as a human artery by rotating an abrasive element within the vessel to partially or completely ablate the unwanted material.

2. Description of the Related Art

Atherosclerosis, the clogging of arteries, is a leading cause of coronary heart disease. Blood flow through the peripheral arteries (e.g., carotid, femoral, renal, etc.), is similarly affected by the development of atherosclerotic blockages. A conventional method of removing or reducing blockages in blood vessels is known as rotational atherectomy. A long guidewire is advanced into the diseased blood vessel and across the stenotic lesion. A hollow drive shaft is then advanced over the guidewire. The distal end of the drive shaft terminates in a burr provided with an abrasive surface formed from diamond grit or diamond particles. The burr is positioned against the occlusion and the drive shaft rotated at extremely high speeds (e.g., 20,000-160,000 rpm). As the burr rotates, the physician slowly advances it so that the abrasive surface of the burr scrapes against the occluding tissue and disintegrates it, reducing the occlusion and improving the blood flow through the vessel. Such a method and a device for performing the method are described in, for example, U.S. Pat. No. 4,990,134 to Auth.

It is also known from U.S. Pat. No. 6,132,444 to Shturman (the instant inventor) et al., to provide a drive shaft with an abrasive element eccentrically positioned proximally to and spaced away from the distal end of the drive shaft.

Rotational angioplasty (atherectomy) is frequently used to remove atherosclerotic or other blocking material from stenotic (blocked) coronary arteries and other blood vessels. However, a disadvantage with this technique is that abraded particles can migrate along the blood vessel distally and block very small diameter vessels including capillaries of the heart muscle itself. The effect of the particulate debris produced by this procedure is of major concern to physicians who practice in this field. Clearly, the existence of particulate matter in the blood stream is undesirable and can cause potentially life-threatening complications, especially if the particles are over a certain size.

Although the potentially detrimental effect caused by the presence of abraded particles in the blood vessels is reduced if they are very small microparticles, it is much more preferable to remove from the treated blood vessel any debris abraded or otherwise released from the stenotic lesion during treatment and thereby prevent migration of debris to other locations along the treated blood vessel.

A rotational atherectomy device, described in U.S. Pat. No. 5,681,336 (to Clement et al.), has been proposed which attempts to prevent migration of abraded particles along the blood stream by removing the ablated material from the blood vessel whilst the device is in use. The rotational atherectomy device known from U.S. Pat. No. 5,681,336 (to Clement et al.) has a complicated construction and is difficult to manufacture on a commercial scale.

A number of disadvantages associated with the known rotational atherectomy devices have been addressed in WO 2006/126076 to Shturman (the instant inventor). The present invention seeks to further improve rotational atherectomy devices known from this document and other disadvantages associated with known atherectomy devices.

SUMMARY

According to the invention, there is provided a rotational atherectomy device for removing a stenotic tissue from a vessel of a patient, the device comprising a rotatable, flexible, hollow drive shaft having a distal end, the drive shaft comprising a fluid impermeable wall, an abrasive element mounted to the drive shaft proximal to and spaced away from its distal end, the fluid impermeable wall being formed from a torque transmitting coil and at least one fluid impermeable membrane which defines a lumen for the antegrade flow of pressurized fluid through the drive shaft and into a distal fluid inflatable support element to inflate said fluid inflatable support element, the distal fluid inflatable support element being located at the distal end of the drive shaft and having an outer wall comprising an outflow opening located such that said outflow opening faces an inner surface of a treated vessel during rotation of the drive shaft so that a flow of fluid out of said opening forms a layer of fluid between the outer wall of the fluid inflatable distal support element and a wall of the treated vessel, said layer of fluid forming a fluid bearing between the outer wall of the rotating fluid inflated distal support element and the wall of the treated vessel.

In one embodiment of the invention, the drive shaft has a longitudinal axis and the distal fluid inflatable support element has a centre of mass spaced radially away from the longitudinal axis of the drive shaft when the distal inflatable support element is fluid inflated. Preferably, in this embodiment, a fluid inflatable space within the distal fluid inflatable support element extends only partially around a circumference of the drive shaft so that, when the distal inflatable support element is inflated with fluid its centre of mass is offset from a longitudinal axis of the drive shaft in one direction so that it acts as a counterweight to the abrasive element, which has its centre of mass offset from the longitudinal axis of the drive shaft in the opposite direction.

In another embodiment, the drive shaft has a longitudinal axis and the distal fluid inflatable support element has a centre of mass coaxial with the longitudinal axis of the drive shaft whenever the distal inflatable support element is fluid inflated. Preferably, in this embodiment, there are a plurality of openings in the outer wall of the fluid inflatable distal support element, said openings being located around the circumference of the outer wall of the fluid inflatable distal support element such that at any time during rotation of the drive shaft a flow of fluid through the opening forms a layer of fluid between the outer wall of the fluid inflatable distal support element and a wall of the treated vessel during rotation of said drive shaft, said layer of fluid forming a fluid bearing between the outer wall of the rotatable fluid inflated distal support element and the wall of the treated vessel.

In any embodiment of the invention, the fluid impermeable drive shaft may be provided with a proximal fluid inflatable support element located proximal to and spaced away from the abrasive element, the membrane that forms a fluid impermeable lumen for the antegrade flow of fluid along the torque transmitting coil into the distal fluid inflatable support element also forming a lumen for the antegrade flow of fluid along the torque transmitting coil into said proximal fluid inflatable support element to inflate said proximal fluid inflatable support element, wherein the proximal fluid inflatable support element has an outer wall formed by one of the fluid impermeable membranes, said outer wall of the proximal fluid inflatable support element having outflow openings located such that, at any time during rotation of the drive shaft and following inflation of the proximal fluid inflatable support element, at least one of said outflow openings is facing an inner surface of a treated vessel so that a flow of fluid through said opening(s) facing an inner surface of the treated vessel forms a layer of fluid between the outer wall of the fluid inflatable proximal support element and a wall of the treated vessel, said layer of fluid forming a fluid bearing between the outer wall of the rotating fluid inflatable proximal support element and the wall of the treated vessel.

In one embodiment the proximal fluid inflatable support element also preferably has a centre of mass spaced radially away from the longitudinal axis of the drive shaft when the proximal inflatable support element is fluid inflated which may be achieved by providing a fluid inflatable space within the proximal fluid inflatable support elements that extends circumferentially only partially around circumferential segments of the drive shaft. In this embodiment, when the proximal fluid inflatable support element is inflated with fluid its centre of mass becomes offset from a longitudinal axis of the drive shaft in one direction so it acts as a counterweight to the abrasive element, which has its centre of mass offset from the longitudinal axis of the drive shaft in the opposite direction.

In another embodiment, the drive shaft has a longitudinal axis and the proximal fluid inflatable support element has a centre of mass coaxial with the longitudinal axis of the drive shaft whenever the proximal inflatable support element is fluid inflated. In this embodiment there are a plurality of openings in the outer wall of the fluid inflatable proximal support element, said openings being located around the circumference of the outer wall of the fluid inflatable proximal support element such that at any time during rotation of the drive shaft a flow of fluid through the opening forms a layer of fluid between the outer wall of the fluid inflatable proximal support element and a wall of the treated vessel during rotation of said drive shaft, said layer of fluid forming a fluid bearing between the outer wall of the rotatable proximal fluid inflated support element and the wall of the treated vessel.

Preferably, in one embodiment, the fluid inflatable space within both the distal and proximal fluid inflatable support elements extends circumferentially only partially around circumferential segments which are spaced away in one direction with respect to the longitudinal axis of the drive shaft so that, when both the distal and proximal fluid inflatable support elements are inflated by fluid, their centers of mass become offset from a longitudinal axis of the drive shaft in said one direction and the distal and proximal fluid inflatable support elements act as counterweights to the abrasive element which is located on the drive shaft between the support elements and has its centre of mass offset from the longitudinal axis of the drive shaft in the opposite direction.

According to another preferred embodiment of the invention in which at least the distal inflatable support element has its centre of mass coaxial with the longitudinal axis of the drive shaft, the abrasive element also has its centre of mass coaxial with a longitudinal axis of the drive shaft. Whenever the centre of mass of the abrasive element is coaxial with a longitudinal axis of the drive shaft, preferably both the distal and proximal inflatable elements also have there centres of mass coaxial with the longitudinal axis of the drive shaft when inflated.

In preferred embodiments, a valve is formed near the distal end of the drive shaft. In the most preferred embodiment, said valve is a flexible leaf valve. The flexible leaf valve is preferably formed integrally with a wall of the distal fluid inflatable support element. The flexible leaf valve is moved to its closed position by pressure of fluid, which is pumped in an antegrade direction through the drive shaft after advancing the drive shaft over a guidewire across a stenotic lesion to be treated and withdrawing the guidewire from the drive shaft.

In one embodiment of the invention the abrasive element and both of the fluid inflatable support elements are symmetric with respect to the rotational (longitudinal) axis of the drive shaft. In another embodiment of the invention the abrasive element and the fluid inflatable support elements have their centres of mass spaced radially away from the rotational (longitudinal) axis of the drive shaft. In yet another embodiment of the invention the abrasive element has its centre of mass spaced away from the rotational (longitudinal) axis of the drive shaft while both of the distal and proximal fluid inflatable support elements have their centres of mass coaxial with the rotational (longitudinal) axis of the drive shaft.

The distal fluid inflatable support element preferably includes at least one inflow opening communicating a lumen of the fluid impermeable drive shaft with an interior space of the distal fluid inflatable support element, said space at least partially defined by a fluid impermeable membrane, the at least one inflow opening preferably having an axis which is perpendicular to a longitudinal axis of the fluid impermeable drive shaft.

In a preferred embodiment, the distal fluid inflatable support element includes at least one outflow opening communicating the interior space of the distal fluid inflatable support element with a vascular space within the vessel of the patient, at least one said outflow opening preferably having an axis which is about perpendicular to a longitudinal axis of the drive shaft when the distal inflatable support element is fluid inflated.

According to yet another aspect of the invention, there is provided a rotational atherectomy device, wherein the drive shaft is provided with a solid proximal support element located proximal to and spaced away from the abrasive element, the membrane that forms a fluid impermeable lumen for the antegrade flow of fluid through the drive shaft into the distal fluid inflatable support element also forming a lumen for the antegrade flow of fluid through the drive shaft into an outflow channel extending through said solid proximal support element, the solid proximal support element having a rounded outer surface, said outflow channel having an outflow opening in the rounded outer surface of the solid proximal support element such that, during rotation of the drive shaft, said outflow opening on the outer surface of the solid proximal support element is facing an inner surface of a treated vessel so that a flow of fluid out of said outflow opening forms a layer of fluid between the solid proximal support element and a wall of the treated vessel during rotation of the drive shaft, said layer of fluid forming a fluid bearing between the rotating solid proximal support element and the wall of the treated vessel.

According to another aspect of the invention, there is provided a rotational atherectomy device for removing a stenotic tissue from a vessel of a patient, the device comprising a turbine housing and a rotatable, flexible, hollow drive shaft having a distal end, a proximal end and, an abrasive element mounted to the drive shaft, the drive shaft comprising a torque transmitting coil and at least one fluid impermeable membrane forming an open-ended fluid impermeable lumen for the antegrade flow of fluid through the drive shaft from the proximal end of the drive shaft towards the distal end of the drive shaft, a proximal end portion of the drive shaft being attached to a distal end portion of a hollow turbine shaft rotatably mounted in the turbine housing, wherein a cylindrical stationary fluid supply tube comprising a distal end is received within the hollow turbine shaft to convey fluid from a pressurized fluid source into the proximal end of the drive shaft, the cylindrical wall of the stationary fluid supply tube having openings therein spaced from its distal end and facing the inner surface of the hollow, rotatable turbine shaft, the openings being configured such that a portion of the fluid flowing in an antegrade direction through the stationary fluid supply tube is re-directed through said openings to form a layer of fluid between the outer surface of the stationary fluid supply tube and the inner surface of the hollow rotatable turbine shaft, said layer of fluid acting as a fluid bearing between the stationary fluid supply tube and the rotatable turbine shaft.

In one embodiment, the openings in the cylindrical wall of the stationary fluid supply tube may extend in a radially outward direction relative to the axis of rotation of the hollow, rotatable turbine shaft.

The cylindrical stationary fluid supply tube is preferably received within the hollow rotatable turbine shaft such that fluid flowing in an antegrade direction out of the distal end of the stationary fluid supply tube traverses a portion of the hollow rotatable turbine shaft prior to flowing into the proximal end of the drive shaft.

According to another aspect of the invention, there is provided a turbine housing for a rotational atherectomy device for removing a stenotic tissue from a vessel of a patient, the turbine housing comprising a stationary cylindrical fluid supply tube received within a hollow rotatable turbine shaft, the cylindrical wall of the stationary fluid supply tube having openings therein spaced from its distal end and facing the inner surface of the hollow, rotatable turbine shaft, the openings being configured such that a portion of the fluid flowing in an antegrade direction through the stationary fluid supply tube is re-directed through said openings to form a layer of fluid between the outer surface of the stationary fluid supply tube and the inner surface of the hollow rotatable turbine shaft, said layer of fluid acting as a fluid bearing between the stationary fluid supply tube and the rotatable turbine shaft.

It should be appreciated that the present invention covers two most preferred embodiments. In a first most preferred embodiment, the fluid inflatable support elements are asymmetrical with respect to the longitudinal axis of the drive shaft and, in a second most preferred embodiment, the fluid inflatable support elements are symmetric with respect to the longitudinal axis of the drive shaft. However, it will be appreciated that, in all the embodiments, the asymmetric and symmetric fluid inflatable elements comprise outflow openings located such that, in the rotating drive shaft, fluid flowing through said openings forms fluid bearings between outer walls of said inflatable elements and the wall of the treated vessel.

It should be noted that throughout this specification, reference is made to “distal” and “proximal” ends and to flow of fluid in an “antegrade” and “retrograde” direction. For the avoidance of doubt, the distal end is considered to refer to the end of the device which is inserted into the vessel in the body of the patient and the proximal end is the end of the device which remains outside the body of the patient and which can be connected to a handle assembly for both rotating and longitudinally moving the drive shaft within the treated vessel. “Antegrade” flow refers to a direction of flow from the proximal towards the distal end of the device. Similarly, “retrograde” flow refers to a direction of flow in the opposite direction, i.e. from the distal towards the proximal end of the device.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of example only, and with reference to the accompanying drawings, in which:

FIG. 1 illustrates in a longitudinal cross-section a distal portion of one preferred embodiment of the rotational atherectomy device of the invention, this embodiment comprising asymmetric fluid inflatable support elements and illustrates location of outflow openings in outer walls of said fluid inflatable support elements, the support elements being located distal and proximal to the abrasive element;

FIG. 2 illustrates the device ofFIG. 1 located in a vessel being treated and showing how the device can be used to abrade a stenotic lesion while forming fluid bearings between outer walls of the asymmetric fluid inflated support elements and the wall of the treated vessel;

FIG. 3 illustrates in a longitudinal cross-section a distal portion of another preferred embodiment of the rotational atherectomy device of the invention, this embodiment comprising symmetric fluid inflatable support elements and illustrates location of outflow openings in outer walls of said fluid inflatable support elements, the support elements being located distal and proximal to the abrasive element;

FIG. 4 illustrates the device ofFIG. 3 located in a vessel being treated and showing how the device can be used in a curved vessel to abrade a stenotic lesion while forming fluid bearings between outer walls of symmetric fluid inflated support elements located distal and proximal to the abrasive element and the wall of the treated vessel;

FIGS. 5 to 7 are enlarged views of portions of the atherectomy device shown inFIG. 4;

FIG. 8 is generally similar toFIG. 3 but shows the formation of a flexible leaf valve, said valve having one or more leaflets;

FIG. 9 is generally similar toFIG. 1 but shows the formation of a flexible leaf valve, said valve having one or more leaflets;

FIG. 10 is generally similar toFIG. 8 but shows a rotational atherectomy device with symmetric fluid inflatable support elements which are formed integrally with a fluid impermeable membrane by using manufacturing methods of injection molding, insertion molding or other currently available progressive manufacturing methods;

FIG. 10A illustrates an embodiment in which the distal end portion of the atherectomy device which incorporates the fluid inflatable elements is injection moulded so that the membrane extending over the torque transmitting coil is separate to the membrane which may line or may extend around the torque transmitting coil proximal to the distal end portion of the device;

FIG. 11 illustrates a cross-sectional view through a turbine housing of the rotational atherectomy device according to the present invention, and shows how a fluid bearing is formed between a distal end segment of a stationary fluid supply tube and a rotatable turbine shaft by providing radially outward directed openings in the wall of the stationary fluid supply tube;

FIG. 12 is an enlarged view of the distal end segment of the stationary fluid supply tube shown inFIG. 11.

DETAILED DESCRIPTION

InFIGS. 1 to 12, the direction of movement of the device is indicated by arrow marked “DM”, the antegrade flow of fluid being indicated by arrows “FF” and the flow of fluid in a retrograde direction is indicated by arrows marked “R”. Abraded particles AP abraded from thestenotic lesion330 are aspirated into a lumen of adrive shaft sheath5000 so that the retrograde flowing fluid and the abraded particles entrained in said fluid can be removed from the treated vessel and out of the patient's body.

FIG. 1 illustrates in a longitudinal cross-section a distal portion of one preferred embodiment of the rotational atherectomy device of the invention. The rotational atherectomy device is comprised of an asymmetricabrasive element1002 which extends around the entire circumference of thedrive shaft2 proximal to and spaced away from a distal end6 of thedrive shaft2. Thedrive shaft2 has a fluidimpermeable membrane3 which linestorque transmitting coil4. Both thetorque transmitting coil4 and the fluidimpermeable membrane3 extend distally beyond theabrasive element1002. The fluidimpermeable membrane3 is folded on itself at the distal end6 of thedrive shaft2 and forms a distal fluidinflatable support element10 between an inner11 and outer22 layers of the foldedmembrane3. Theouter layer22 of themembrane3 forms anouter wall222 of the distal fluidinflatable support element10 and theinner layer11 of themembrane3 forms aninner wall111 of the distal fluidinflatable support element10. Theinner wall111 of the distal fluidinflatable support element10 has at least one inflow aperture (opening)15 therein. Theinflow aperture15 of the distal fluidinflatable support element10 communicates a fluid impermeable lumen of thedrive shaft2 with a fluidinflatable space3000 of the distal fluidinflatable support element10.FIG. 1 illustrates that a portion of flushing fluid FF flowing in an antegrade direction through thedrive shaft2 is redirected through theinflow aperture15 into the distal fluidinflatable support element10 to inflate said distalinflatable support element10.

It should be noted that the inner andouter layers11,22 of the folded membrane may be formed by either folding themembrane3 back onto itself or by inverting it.

FIG. 1 best illustrates that in order to form the distal fluidinflatable support element10, the inner andouter layers11,22 of the folded fluidimpermeable membrane3 are connected or bonded to each other at least just proximal to the distal fluidinflatable support element10. In this location, just proximal to the distal fluidinflatable support element10, the inner andouter layers11,22 of themembrane3 are preferably connected or bonded to each other around the entire circumference of thedrive shaft2.

In the most preferred embodiment of the invention theouter wall222 of the distal fluidinflatable support element10 has at least oneoutflow opening20 which enables flow of fluid out of the distended fluid inflatabledistal support element10. The distal fluidinflatable support element10 becomes distended by flow of fluid through theinflow aperture15 in itsinner wall111. Theinflow aperture15 communicates a fluid impermeable lumen of thedrive shaft2 with aninflatable space3000 within the distal fluidinflatable support element10, saidinflatable space3000 is at least partially defined by a fluid impermeable membrane which forms theouter wall222 of the distal fluidinflatable support element10.

An area of theinflow aperture15 through which fluid enters the distalinflatable support element10 is larger than the area of the outflow opening(s)20 through which fluid exits the distal fluidinflatable support element10 so that the distal fluidinflatable support element10 is kept inflated by the pressure of fluid flowing through the distal fluidinflatable support element10.

FIG. 1 shows the distal fluidinflatable support element10 in its inflated state.FIG. 1 illustrates that the distal fluidinflatable support element10 is asymmetric with respect to a longitudinal axis W-W of thedrive shaft2. After being inflated by fluid, such asymmetric distal support element has its centre of mass CM spaced away from the longitudinal axis W-W of thedrive shaft2.FIG. 1 shows anabrasive element1002 which is mounted to thedrive shaft2 proximal to and spaced away from the asymmetric distal fluidinflatable support element10. Theabrasive element1002 extends around the entire circumference of thedrive shaft2 and has its centre of mass spaced radially away from the longitudinal axis W-W of the drive shaft. Preferably, the centre of mass CM of the asymmetric fluid inflateddistal support element10 is spaced radially away from the longitudinal axis W-W of the drive shaft in one direction and the centre of mass of theabrasive element1002 is spaced radially away from the longitudinal axis W-W of the drive shaft in another diametrically opposite direction, so that in a rotating drive shaft such asymmetric fluid inflateddistal support element10 becomes a distal fluid inflatable counterweight with respect to theabrasive element1002.

FIG. 1 illustrates that theouter wall222 of the fluid inflateddistal support element10 is bowing longitudinally outwards at least along its longitudinally middle section which extends in a longitudinal cross-section between anoutflow opening20 which is located longitudinally most distally within theouter wall222 and anotheroutflow opening20 which is located longitudinally most proximally within theouter wall222.

Eachoutflow opening20 in theouter wall222 of the distal fluid inflatable support element has its own axis K-K.FIG. 1 illustrates that the asymmetric distal fluidinflatable support element10 when inflated has at least oneoutflow opening20 in its longitudinally roundedouter wall222 located such that the axis K-K of theoutflow opening20 forms an acute angle of at least sixty (60) degrees with respect to the longitudinal axis W-W of thedrive shaft2. In the most preferred embodiment of the invention, the asymmetric distal fluidinflatable support element10 when inflated has at least oneoutflow opening20 in itsouter wall222 located such that the axis K-K of theoutflow opening20 forms an angle α of about ninety (90) degrees with respect to the longitudinal axis W-W of the drive shaft.

FIG. 2 illustrates that in the rotating asymmetric fluid inflateddistal support element10 at least one of the above describedoutflow openings20 is located such that its axis forms about a ninety (90) degrees angle with respect to the inner surface of thewall300 of the treated vessel. Centrifugal force attempts to press a rotating asymmetric fluid inflateddistal support element10 against thewall300 of the treated vessel, but fluid exiting from theoutflow opening20 along its axis at an angle of about ninety (90) degrees with respect to thewall300 of the vessel forms a thin layer of fluid between theouter wall222 of the fluid inflateddistal support element10 and an inner surface of thewall300 of the vessel. Preferably, the fluid inflateddistal support element10 with the centre of mass radially spaced away from the longitudinal (rotational) axis of the drive shaft should have at least oneoutflow opening20 in theouter wall222 of the distalinflatable support element10 located such that at any time during rotation of thedrive shaft2 saidoutflow opening20 is facing an inner surface of the treated vessel so that a flow of fluid through theopening20 forms a layer of fluid between theouter wall222 of the rotating fluid inflateddistal support element10 and the wall of a treated vessel. Said layer of fluid forms a fluid bearing between theouter wall222 of the rotating fluid inflateddistal support element10 and the wall of the treated vessel.

It should be noted that in the most preferred embodiments of the invention, the fluid impermeable drive shaft is provided with two fluid inflatable support elements, one located at the distal end of the drive shaft and the other proximal to and spaced away from the abrasive element.FIG. 1 illustrates one such embodiment in which thedrive shaft2 is provided with both a distal fluidinflatable support element10 and a proximal fluidinflatable support element10p. The proximal fluidinflatable support element10phas aninner wall111pand anouter wall222p. In the most preferred embodiment of the invention, theouter wall222pof the proximal fluidinflatable support element10pis formed by theouter layer22 of the folded fluidimpermeable membrane3. Theinner wall111pof the proximal fluidinflatable support element10pis formed by theinner layer11 of the folded fluidimpermeable membrane3. Theinner wall111pof the proximal fluidinflatable support element10phas aninflow aperture15ptherein.FIG. 1 illustrates that a portion of flushing fluid FF flowing in an antegrade direction through thedrive shaft2 is redirected through theinflow aperture15pinto the proximal fluidinflatable support element10pto inflate said proximal fluid inflatable support element.FIG. 1 illustrates best that in order to form the proximal fluidinflatable support element10p, the inner11 and outer22 layers of the folded fluidimpermeable membrane3 are connected or bonded to each other at least just distal and proximal to the proximal fluidinflatable support element10p. In this location, just distal and proximal to the proximal fluidinflatable support element10p, the inner11 and the outer22 layers of themembrane3 are preferably connected or bonded to each other around the entire circumference of thedrive shaft2.

It should be noted that the outer wall of the proximal fluid inflatable support element may be formed not only by a proximal portion of theouter layer22 of the folded fluidimpermeable membrane3, but by a separate fluid impermeable membrane connected or bonded circumferentially to the fluidimpermeable membrane3 at least just distal and proximal to the proximal fluid inflatable support element.

The following discussion is focused on the design and function of the proximal fluidinflatable support element10pwhich has itsouter wall222pformed by theouter layer22 of the folded fluidimpermeable membrane3, but it should be understood that the same discussion would be applicable to a proximal fluid inflatable support element which has its outer wall formed by the separate fluid impermeable membrane. The following discussion is particularly applicable with respect to the location and function of openings in the outer wall of the proximal fluid inflatable support element.

In the most preferred embodiment of the invention theouter wall222pof the proximal fluidinflatable support element10phas at least oneoutflow opening20pwhich enables flow of fluid out of the distended fluid inflatableproximal support element10p. The proximal fluidinflatable support element10pbecomes distended by flow of fluid through itsinflow aperture15pwhich communicates the lumen of the fluidimpermeable drive shaft2 with theinflatable space3000pwithin the proximal fluidinflatable support element10p. The fluidinflatable space3000pis at least partially defined by a fluid impermeable membrane which forms anouter wall222pof the proximal fluidinflatable support element10p.

An area of theinflow aperture15pthrough which fluid enters the proximal fluidinflatable support element10pis larger than the area of the outflow opening(s)20pthrough which fluid exits the proximal fluidinflatable support element10pso that the proximal fluidinflatable support element10pis kept inflated by the pressure of the fluid flowing through the proximal fluidinflatable support element10p.

FIG. 1 shows the proximal fluidinflatable support element10pin its inflated state.FIG. 1 illustrates that the proximal fluidinflatable support element10pis asymmetric with respect to a longitudinal axis of the drive shaft. After being inflated by fluid, such asymmetricproximal support element10phas its centre of mass CMp spaced away from the longitudinal axis W-W of thedrive shaft2.FIG. 1 shows anabrasive element1002 which is mounted to thedrive shaft2 distal to and spaced away from the asymmetric proximal fluidinflatable support element10p. The asymmetricabrasive element1002 extends around the entire circumference of thedrive shaft2 and has its centre of mass spaced radially away from the longitudinal axis W-W of thedrive shaft2. Preferably, the centre of mass CMp of the asymmetric fluid inflatedproximal support element10pis spaced radially away from the longitudinal axis W-W of the drive shaft in one direction and the centre of mass of the asymmetricabrasive element1002 is spaced radially away from the longitudinal axis W-W of thedrive shaft2 in another diametrically opposite direction, so that in a rotating drive shaft such asymmetric fluid inflatedproximal support element10pbecomes a proximal fluid inflatable counterweight with respect to theabrasive element1002.

FIG. 1 illustrates that theouter wall222pof the fluid inflatedproximal support element10pis bowing longitudinally outwards at least along its longitudinally middle section which extends in a longitudinal cross-section between anoutflow opening20pwhich is located longitudinally most distally within theouter wall222pand anotheroutflow opening20pwhich is located longitudinally most proximally within theouter wall222p.

Eachoutflow opening20pin theouter wall222pof the proximal fluid inflatable support element has its own axis L-L.FIG. 1 illustrates that the asymmetric proximal fluidinflatable support element10pwhen inflated has at least oneoutflow opening20pin itsouter wall222plocated such that the axis L-L of theoutflow opening20pforms an acute angle of at least sixty (60) degrees with respect to the longitudinal axis W-W of thedrive shaft2. In the most preferred embodiment of the invention, the asymmetric proximal fluidinflatable support element10pwhen inflated has at least oneoutflow opening20pin itsouter wall222plocated such that the axis L-L of theoutflow opening20pforms about a ninety (90) degrees angle α with respect to the longitudinal axis W-W of thedrive shaft2.FIG. 2 illustrates that in the rotating asymmetric fluid inflatedproximal support element10pat least one of the above describedoutflow openings20pis located such that its axis forms about a ninety (90) degrees angle with respect to the inner surface of thewall300 of the treated vessel. Centrifugal force attempts to press a rotating asymmetric fluid inflatedproximal support element10pagainst thewall300 of the treated vessel, but fluid exiting from theoutflow opening20palong its axis at an angle of about ninety (90) degrees with respect to thewall300 of the vessel forms a thin layer of fluid between the roundedouter wall222pof the fluid inflatedproximal support element10pand an inner surface of thewall300 of the vessel.

FIG. 2 illustrates rotation of the fluid inflatedproximal support element10pwith the centre of mass radially spaced away from the longitudinal (rotational) axis of the drive shaft. Centrifugal force attempts to press the rotating fluid inflatedproximal support element10pagainst thewall300 of the vessel, but at least oneoutflow opening20pin the longitudinally roundedouter wall222pof the rotating fluid inflatedproximal support element10pis located such that a flow of fluid through saidopening222pforms a layer of fluid between theouter wall222pof the rotating fluid inflatedproximal support element10pand thewall300 of the treated vessel. Preferably, the fluid inflatedproximal support element10pwith the centre of mass radially spaced away from the longitudinal (rotational) axis of thedrive shaft2 should have at least oneoutflow opening20pin the longitudinally roundedouter wall222pof the proximalinflatable support element10plocated such that at any time during rotation of thedrive shaft2 saidoutflow opening20pis facing an inner surface of the treated vessel so that a flow of fluid through theoutflow opening20pforms a layer of fluid between the longitudinally roundedouter wall222pof the rotating fluid inflatedproximal support element10pand thewall300 of a treated vessel. Said layer of fluid forms a fluid bearing between theouter wall222pof the rotating fluid inflatedproximal support element10pand thewall300 of the treated vessel.

FIG. 3 illustrates another preferred embodiment of the distal end portion of the rotational atherectomy device of the invention. In this embodiment both theabrasive element1001 and the distal fluidinflatable support element10sare symmetric with respect to a longitudinal axis W-W of the drive shaft. The symmetricabrasive element1001 extends around the entire circumference of thedrive shaft2 and is located proximal to and spaced away from the symmetric distal fluidinflatable support element10s. The symmetric distal fluidinflatable support element10shas a fluidinflatable space3000swhich extends uniformly around thedrive shaft2, so that after being inflated by fluid thedistal support element10shas its centre of mass coaxial with the longitudinal axis W-W of thedrive shaft2. Aninflow aperture15scommunicates the fluidinflatable space3000swithin the fluidinflatable support element10swith the lumen of the fluidimpermeable drive shaft2. The fluidinflatable space3000sis defined by a fluid impermeable membrane which forms at least a portion of thewall222sof the symmetric distal fluidinflatable support element10s.

FIG. 3 illustrates in a longitudinal cross-section that the symmetric fluid inflatable support element has a maximum diameter circumference when inflated and that theouter wall222sof the fluid inflated symmetricdistal support element10sis bowing longitudinally outward at least along the maximum diameter circumference of the fluid inflated symmetric distal support element. Theouter wall222sof the symmetric distal fluidinflatable support element10shas at least oneoutflow opening20s. Preferably, the symmetric distal fluidinflatable support element10shas at least twooutflow openings20sin itsouter wall222s. Eachoutflow opening20sin theouter wall222sof the symmetric distal fluidinflatable support element10shas its own axis M-M. The Figure illustrates that the symmetric distal fluidinflatable support element10s, when inflated, has at least oneoutflow opening20sin itsouter wall222slocated such that the axis M-M of theoutflow opening20sforms an acute angle of at least sixty (60) degrees with respect to the longitudinal axis W-W of thedrive shaft2. In the most preferred embodiment of the invention, the symmetric distal fluidinflatable support element10swhen inflated has at least oneoutflow opening20sin itsouter wall222slocated such that the axis M-M of theoutflow opening20sforms about a ninety (90) degrees angle α with respect to the longitudinal axis W-W of the drive shaft.

FIGS. 4 and 5 illustrate that in the rotating symmetric fluid inflateddistal support element10sat least one of the above describedoutflow openings20sis located such that its axis M-M forms about a ninety (90) degrees angle with respect to the inner surface of thewall300 of the treated vessel.FIGS. 4 and 5 also illustrate that in a curved vessel thedrive shaft2 attempts to maintain its straight configuration and therefore attempts to press a rotating symmetric distal fluid inflatedsupport element10sagainst the outer curvature of the vessel but fluid exiting from theoutflow opening20salong its axis M-M at an angle of about ninety (90) degrees with respect to thewall300 of the vessel forms a thin layer of fluid between theouter wall222sof the fluid inflateddistal support element10sand the inner surface of the outer curvature of thewall300 of the treated vessel.

Preferably, the fluid inflated symmetricdistal support element10sshould have at leastfew outflow openings20slocated around the circumference of theouter wall222s, theoutflow openings20slocated in a longitudinally bowing outward segment of theouter wall222ssuch that at any time during rotation of thedrive shaft2 at least one of theseoutflow openings20sis facing an inner surface of the treated vessel so that a flow of fluid through theoutflow opening20sforms a layer of fluid between theouter wall222sof the rotating fluid inflated symmetricdistal support element10sand thewall300 of the treated vessel. Said layer of fluid forms a fluid bearing between theouter wall222sof the rotating fluid inflateddistal support element10sand thewall300 of the treated vessel.

It should be noted that in the most preferred embodiments of the invention, the fluid impermeable drive shaft is provided with two symmetric fluid inflatable support elements, one located at the distal end of the drive shaft and the other proximal to and spaced away from theabrasive element1001.FIG. 3 illustrates one such embodiment in which thedrive shaft2 is provided with both a symmetric distal fluidinflatable support element10sand a symmetric proximal fluidinflatable support element10sp. The symmetric proximal fluidinflatable support element10sphas aninner wall111spand anouter wall222sp. In the most preferred embodiment of the invention, theouter wall222spof the symmetric proximal fluidinflatable support element10spis formed by theouter layer22 of the folded fluidimpermeable membrane3. Theinner wall111spof the symmetric proximal fluidinflatable support element10spis formed by theinner layer11 of the folded fluidimpermeable membrane3. Theinner wall111spof the symmetric proximal fluidinflatable support element10sphas aninflow aperture15sptherein. Thisinflow aperture15spcommunicates the lumen of the fluidimpermeable drive shaft2 with aninflatable space3000spwithin the symmetric proximal fluidinflatable support element10sp. Theinflatable space3000spis at least partially defined by a fluid impermeable membrane which forms theouter wall222spof the symmetric proximal fluidinflatable support element10sp.FIG. 3 illustrates that a portion of flushing fluid FF flowing in an antegrade direction through thedrive shaft2 is redirected through theinflow aperture15spinto the symmetric proximal fluidinflatable support element10spto inflate said symmetric proximal fluid inflatable support element.FIG. 3 illustrates best that in order to form the symmetric proximal fluidinflatable support element10sp, the inner11 and outer22 layers of the folded fluidimpermeable membrane3 are connected or bonded to each other at least just distal and proximal to the symmetric proximal fluidinflatable support element10sp. In this location, just distal and proximal to the symmetric proximal fluidinflatable support element10sp, the inner11 and the outer22 layers of themembrane3 are preferably connected or bonded to each other around the entire circumference of thedrive shaft2.

It should be noted that theouter wall222spof the symmetric proximal fluidinflatable support element10spmay be formed not only by a proximal portion of theouter layer22 of the folded fluidimpermeable membrane3, but by another fluid impermeable membrane.

Theouter wall222spof the symmetric proximal fluidinflatable support element10sphas at least oneoutflow opening20sp. Preferably, the symmetric proximal fluidinflatable support element10sphas at least twooutflow openings20spin itsouter wall222sp. Eachoutflow opening20spin theouter wall222spof the symmetric proximal fluidinflatable support element10sphas its own axis N-N.FIG. 3 illustrates that the symmetric proximal fluidinflatable support element10spwhen inflated has at least oneoutflow opening20spin itsouter wall222splocated such that the axis N-N of theoutflow opening20spforms an acute angle of at least sixty (60) degrees with respect to the longitudinal axis W-W of the drive shaft. In the most preferred embodiment of the invention, the symmetric proximal fluidinflatable support element10spwhen inflated has at least oneoutflow opening20spin itsouter wall222splocated such that the axis N-N of theoutflow opening20spforms about a ninety (90) degrees angle α with respect to the longitudinal axis W-W of thedrive shaft2.FIGS. 4 and 7 illustrate that in the rotating symmetric fluid inflatedproximal support element10spat least one of the above describedoutflow openings20spis located such that its axis N-N forms about a ninety (90) degrees angle with respect to the inner surface of thewall300 of the treated vessel.FIGS. 4 and 7 also illustrate that in a curved vessel thedrive shaft2 attempts to maintain its straight configuration and therefore attempts to press a rotating symmetric proximal fluid inflatedsupport element10spagainst the outer curvature of the vessel but fluid exiting from theoutflow opening20spalong its axis N-N at an angle of about ninety (90) degrees with respect to thewall300 of the vessel forms a thin layer of fluid between theouter wall222spof the fluid inflatedproximal support element10spand an inner surface of thewall300 of the vessel.

Preferably, the fluid inflated symmetricproximal support element10spshould have at leastfew outflow openings20spspaced about equally around the circumference of theouter wall222sp, the openings located such that at any time during rotation of thedrive shaft2 at least one of theseoutflow openings20spis facing an inner surface of the treated vessel so that a flow of fluid through theoutflow opening20spforms a layer of fluid between theouter wall222spof the rotating fluid inflated symmetricproximal support element10spand thewall300 of the treated vessel. Said layer of fluid forms a fluid bearing between theouter wall222spof the rotating fluid inflatedproximal support element10spand thewall300 of the treated vessel.

FIG. 4 illustrates that in a curved vessel thedrive shaft2 attempts to maintain its straight configuration and therefore attempts to press a rotatingabrasive element1001 towards the inner curvature of a curved vessel. As known from WO 2006/126076 this allows preferential removal ofstenotic lesion330 located along the inner curvature of the treated vessel. It is also known from WO 2006/126076 that magnetic forces MF, shown inFIG. 4, may be used to bias abrasive element in any desirable direction with respect to the circumference of the treated vessels.

It should be noted that the rotational atherectomy device comprising symmetrical fluid inflatable support elements may also be used successfully in a straight vessel where said elements, when supported by fluid bearings, allow safe rotation of the drive shaft within the treated vessel even after theguidewire5001 has been removed from the rotational atherectomy device (refer, for example, toFIG. 4). The rotational atherectomy device with symmetric fluid inflatable support elements preferably comprises either an eccentric abrasive element with a centre of mass spaced away from the longitudinal axis of the drive shaft or, an abrasive element which is capable of being magnetically biased in any direction with respect to the circumference of the treated vessel.

FIG. 8 illustrates a fluid impermeable drive shaft with two symmetric fluid inflatable support elements and an asymmetricabrasive element1002 mounted on the drive shaft between said symmetric fluid inflatable support elements.FIG. 8 also shows at least onevalve88 located at the distal end of the lumen of the fluidimpermeable drive shaft2. Thisvalve88 may be comprised of one or more flexible leaflets and is shown in its closed position, thereby preventing flow of flushing fluid through the distal end of the drive shaft and assisting in directing the flushing fluid into the distal symmetric fluid inflatable support element.

FIG. 9 illustrates that avalve77 which is similar tovalve88 may be formed at the distal end of a lumen of the drive shaft with the asymmetric fluidinflatable support elements10 and10p. Thevalve77 may be comprised of one or more leaflets.FIG. 9 also illustrates that aseparate membrane25 may extend around thedrive shaft2 proximal to the distal fluidinflatable support element10. Preferably, theseparate membrane25 is fluid impermeable so that it can form anouter wall222pof the proximal fluidinflatable support element10p. If the distal fluidinflatable element10 is formed from astretchable membrane3 then themembrane25 should be made from a non-stretchable material.

FIG. 10 shows a rotational atherectomy device with symmetric fluid inflatable support elements which are formed integrally with a fluidimpermeable membrane3 without folding the membrane on itself at the distal end of the drive shaft but instead making said inflatable support elements integral with themembrane3 by using manufacturing methods of injection molding, insertion molding or other currently available progressive manufacturing methods. It should be understood that similar progressive manufacturing methods may be used in producing a rotational atherectomy device with asymmetric fluid inflatable support elements.

FIG. 10A illustrates an embodiment in which the distal end portion of the atherectomy device, which incorporates the fluid inflatable elements, is injection moulded so that themembrane3003 extending over the torque transmitting coil along the distal end portion of the device is separate to the membrane which may line or may extend over the torque transmitting coil proximal to the distal end portion of the device.

FIG. 2 illustrates that an orbit of the asymmetric abrasive element may be biased, in any direction with respect to the circumference of the treated vessel, by an external magnetic force illustrated by arrows MF.FIG. 4 illustrates that the position of the symmetricabrasive element1001 with respect to the circumference of the vessel also may be affected by an external magnetic force illustrated by arrows MF. It should be understood that the external magnetic force may be utilized to move in the desired direction any of the abrasive elements described above and shown inFIGS. 1 through 9.

FIGS. 11 and 12 illustrate that a wall of the stationaryfluid supply tube32 preferably should have at least three openings located near its distal end and equally spaced around the circumference of thefluid supply tube32.FIGS. 11 and 12 illustrate an embodiment with at least foursuch openings299.FIG. 12 illustrates that eachopening299 has an axis P-P which is perpendicular to a longitudinal (rotational) axis W-W of thefluid supply tube32.FIG. 11 illustrates that a flow of fluid throughopenings299 forms a fluid bearing between the stationaryfluid supply tube32 and therotatable turbine shaft18. Theturbine shaft18 is connected to a flexible, hollow, fluidimpermeable drive shaft2. It should be noted that the most proximal portion of the fluidimpermeable drive shaft2 is shown inFIG. 11.

Many modifications and variations of the invention falling within the terms of the following claims will be apparent to a person skilled in the art and the foregoing description should be regarded as a description of the preferred embodiments only.

Claims (16)

The invention claimed is:

1. A system for performing rotational atherectomy to remove stenotic lesion material from a blood vessel of a patient, the system comprising:

an elongate drive shaft sheath defining a sheath lumen therethrough, the drive shaft sheath being configured to be at least partially disposed within the blood vessel;

a rotational atherectomy device slidable through the elongate drive shaft sheath toward stenotic lesion material in a blood vessel, comprising:

an elongate flexible drive shaft including: a torque-transmitting coil defining a central lumen and a longitudinal axis, and a fluid impermeable membrane surrounding a portion of the torque-transmitting coil, the drive shaft configured for rotation about the longitudinal axis, wherein a first portion of the drive shaft is configured to be disposed within the sheath lumen while a distal portion of the drive shaft extends distally of the sheath lumen when the system is used for performing the rotational atherectomy, wherein the torque-transmitting coil is exposed along an exterior circumference of the first portion of the drive shaft while the fluid impermeable membrane surrounds the torque-transmitting coil along an exterior circumference of the distal portion of the drive shaft;

an abrasive element that is fixed to the distal portion of the drive shaft such that a center of mass of the abrasive element is offset from the longitudinal axis of the drive shaft;

a distal stability element that is fixed to the distal portion of the drive shaft and that has a center of mass aligned with the longitudinal axis of the drive shaft, the distal stability element being distally spaced apart from the abrasive element by a distal separation distance; and

a guidewire removable from the drive shaft of the rotational atherectomy device after the drive shaft is advanced over the guidewire across the stenotic lesion material in the blood vessel.

2. The system ofclaim 1, where the guidewire is configured to be slidably withdrawn from the central lumen of the drive shaft.

3. The system ofclaim 1, wherein an outer surface of the abrasive element is an abrasive outer surface configured to abrade a stenotic lesion and an outer surface of the distal stability element is provided by the fluid impermeable membrane.

4. The system ofclaim 1, wherein the rotational atherectomy device further comprises a proximal stability element that is fixed to the drive shaft and that has a center of mass aligned with the longitudinal axis of the drive shaft, the proximal stability element being proximally spaced apart from the abrasive element by a proximal separation distance.

5. The system ofclaim 4, wherein the proximal and distal stability elements comprise inflatable stability elements.

6. The system ofclaim 4, wherein the proximal and distal stability elements are generally round and surround the torque-transmitting coil of the drive shaft.

7. The system ofclaim 6, wherein the proximal and distal stability elements have an exterior surface that is smoother and different from an abrasive exterior surface of the abrasive element.

8. The system ofclaim 6, wherein at least one of the proximal and distal stability elements comprises a fluid output port in fluid communication with the central lumen of the drive shaft.

9. The system ofclaim 1, wherein the central lumen of the drive shaft is configured to provide a fluid impermeable path to the distal portion of the drive shaft.

10. The system ofclaim 1, wherein the fluid impermeable member provides an exterior wall of the distal stability element.

11. The system ofclaim 10, wherein the distal stability element has an exterior surface that is smoother and different from an abrasive exterior surface of the abrasive element.

12. The system ofclaim 1, wherein the distal stability element comprises an inflatable stability element.

13. The system ofclaim 1, wherein the distal stability element is generally round and surrounds the torque-transmitting coil of the drive shaft.

14. The system ofclaim 1, wherein the distal stability element comprise a fluid output port in fluid communication with the central lumen of the drive shaft.

15. The system ofclaim 1, wherein the abrasive element comprises a solid body that extends around the torque-transmitting coil of the drive shaft.

16. The system ofclaim 1, wherein the fluid impermeable membrane is folded on itself at the distal portion of the drive shaft so as to form the distal stability element between inner and outer layers of a folded region of the fluid impermeable membrane.

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